I used to travel for work and when we were in Manchester the hotel we used was one of those used by the JK production team.
Not all of the guests knew why they were there, they were either told false reasons or they weren't told at all, just that they'd find out on the day but they were led to believe it would be something good.
They had a tab at the hotel bar and were encouraged to use it, they would also have rooms at opposite ends of the hotel. I don't know if the production stirred things up but there would inevitably be arguments, people looking for each others rooms, loud behaviour, and so on.
They would be picked up from the hotel much earlier than they'd been told they were getting picked up so they'd think they had time to wake up, get ready, eat, etc ready to be picked up at a certain time and instead the production team would rock up to unexpectedly knock them out of bed much earlier than agreed.
This is all based on what we saw and what we heard from the guests themselves. We used to groan when we saw Manchester as the meeting location because we knew it would be that hotel and that it would be a shitty night. The whole night before the show and rhen the morning after seemed designed to make sure the guests were potentially hungover and as tired, stressed, and dishevelled looking as possible.